Now this is a question I regularly hear during workshops, so I decided to explain the differences in a blog.
To be honest : you can knot with whatever cord you like, BUT there are some consequences : )
Personally I always use polyester cords from Linhasita, 1mm and 0.5mm.
This post focuses on cords for micro macrame only, but some pics are of thicker cords just to make my point more clear and visible!
1 . Polyester/Nylon or Cotton/Hemp/etc? The reason I use polyester cords is I can cut the ends very short and burn them. That way they melt a little and never fray out. If you would like to use natural cord, you'll have to find another way to hide and lock the ends, for example with glue. I didn't experiment with the natural cords yet, but they have a nice feel and are more eco-friendly!
2. Round or Flat? Round cords are easier to get through the often little holes of the brass beads, it's as simple as that! They also give more 'structure' to a piece. Especially with the 1mm, the different knots are more visible and in my opinion this makes the vibe of the jewel more tribal. On the other hand, if you love a certain kind of smoothness, I would recommend the flat cord (but be aware of the fact that the use of very tiny beads is quite challenging if not impossible).
3. Twined or Braided? This goes together with the cords being flat or round, as mostly for micro macrame, the round cords are twined and the flat cords are braided. So there isn't much of a choice in this. If you choose a round cord it will be twined and if you choose a flat cord it will be braided, as far as I know.
4. Waxed or Non-Waxed? Especially in the beginning waxed cords are easier to handle. You can just put them where you want and they stay. Non-waxed cords curl into each other and don't just stay where you want them, haha, unless you use a lot of pins to tame them!! Also, with the waxed cords, the knots are more locked. If you like more vibrant colors and more shine, you'll have to use the non-waxed cords.
5. Thickness? Most common are 1mm and 0.5mm, but anything is possible. Very fine details or very tiny crystals are happier with the 0.5mm. Massive stones or designs may ask for 1mm. For beginners I mostly advice 1mm. The smaller the cord, the more difficult to see what you're doing.
These are the most frequent differences, but if you have more questions about the cords, don't hesitate to ask me!! I like to order my cords at Ayllu Artesania (www.aylluartesania.es). They are based in Barcelona and Madrid. You'll find all kinds of cords, beads and stones there!! Prices are the lowest I have encountered in all the years of knotting, only the shippingcosts are quite high (free shipping for orders >€500). Most of the times I order together with some friends, and we split the shipping costs. One spool Linhasita 1mm is €3.5 and 0.5mm is €4.
Linhasita 1mm spool = 180meters. About 170 colors to choose from.
Linhasita 0.5mm spool = 334meters. About 117 colors to choose from.
The website is in Spanish though. You'll have to look for : 'Categoria' 'Hilos Encerados Linhasita'
Knots of Cords